1. Field of the Invention
The present invention relates generally to a combination lock formed with a plurality of disk dials to be operated for locking or unlocking.
In general, there are two types of such combination locks. One is of a padlock type having a shackle. The other is of a cylinder type which comprises a first body of a cylindrical configuration formed with a key bore open at one end thereof and connected at the other end thereof with one end of a chain, wire cable or the like loop member, and a second body to be connected with the other end of the loop member and having a key-like projection to be inserted in the first body through the key bore. The present invention relates particulalry to the latter type combination lock.
The invention further relates to a cylinder type combination lock which may allow for a user to select a desired dial combination for unlocking.
2. Description of the Prior Art
Various cylinder type combination locks have been proposed and widely employed for lacking bicycles and the like. For instance U.S. Design Pat. Nos. 231,078, 231,079, 239,079 and 320,711 to the present inventor disclose such types of combination locks. In order to unlock such a conventional lock, the user must angularly move ring dials so as to arrange a series of numerical figures in a line on the peripheral surface of the dials at a predetermined dial setting position. This dial setting operation for unlocking is not only troublesome due to the fact that such conventional combination locks have four or more setting dials for the purpose of increasing the number of possible combinations, but also difficult or impossible in dark places or at night. Therefore, the user is apt to lock his combination lock by turning only one or two ring dials, above all when he is in a hurry, which may result in a possible theft.
The present inventor has proposed in U.S. Pat. No. 4,445,348 issued May 1, 1984, cylinder type combination lock in which the dial combination for unlocking can freely be set or changed by the user. According to such a combination lock, the user may set a desired dial combination, for instance numbers corresponding to his birthday, telephone number, house number or the like so that he will not forget the unlocking dial combination. However, this combination lock is disadvantageous in that it is not suitable to carry out its unlocking operation in dark situations and that the structure is relatively complicated thereby increasing its manufacturing cost.